The vertical and transverse cracks are not allowed for fully prestressed and class A prestressed concrete beams. In order to evaluate the safety performance of a highway bridge, a vibrating wire sensor system was used for long-term online monitoring of the deflection, strain and crack width of a prestressed concrete T-shaped beam bridge. Combined with the bridge load test, the long-term monitoring data was quantitatively analyzed. The results show that under actual operating conditions, the ratio of the maximum deflection to the span of the girder is less than 1/3 000, and the strain increment due to seasonal temperature variation is equivalent to the increment of vehicle’s load. The width of the transverse crack at the bottom of the beam is stable. The research results can provide a technical support for the maintenance of bridges.%全预应力与A类预应力混凝土梁不允许产生梁体竖向、横向裂缝,为评估带裂缝工作预应力混凝土T梁桥的安全性能,对某高速预应力混凝土T梁桥挠度、应变和裂缝宽度采用振弦式传感器进行长期在线监测,结合桥梁荷载试验,对长期监测数据进行定量分析.研究结果表明实际运营条件下,主梁最大挠度与跨径之比小于1/3 000,季节温度变化引起的应变增量与车辆荷载增量相当,梁底横向裂缝宽度变化处于稳定状态.研究成果可为类似桥梁养护管理和维修加固提供技术支持.
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